body {
    display: inline;
    justify-content: center;
    min-height: 100vh;
    background:url(图片/0.png) no-repeat;
    background-size:100% 100%; 
    background-attachment: fixed;
  }
  
  .stars {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 120%;
    transform: rotate(-45deg);
  }
  
  .star {
    --star-color: var(--primary-color);
    --star-tail-length: 6em;
    --star-tail-height: 2px;
    --star-width: calc(var(--star-tail-length) / 6);
    --fall-duration: 9s;
    --tail-fade-duration: var(--fall-duration);
    position: absolute;
    top: var(--top-offset);
    left: 0;
    width: var(--star-tail-length);
    height: var(--star-tail-height);
    color: var(--star-color);
    background: linear-gradient(45deg, currentColor, transparent);
    border-radius: 50%;
    filter: drop-shadow(0 0 6px currentColor);
    transform: translate3d(104em, 0, 0);
    animation: fall var(--fall-duration) var(--fall-delay) linear infinite, tail-fade var(--tail-fade-duration) var(--fall-delay) ease-out infinite;
  }
  @media screen and (max-width: 750px) {
    .star {
      animation: fall var(--fall-duration) var(--fall-delay) linear infinite;
    }
  }
  .star:nth-child(1) {
    --star-tail-length: 6.64em;
    --top-offset: 42.98vh;
    --fall-duration: 10.473s;
    --fall-delay: 4.41s;
  }
  .star:nth-child(2) {
    --star-tail-length: 6.44em;
    --top-offset: 31.36vh;
    --fall-duration: 8.426s;
    --fall-delay: 8.298s;
  }
  .star:nth-child(3) {
    --star-tail-length: 5.97em;
    --top-offset: 77.97vh;
    --fall-duration: 9.542s;
    --fall-delay: 5.036s;
  }
  .star:nth-child(4) {
    --star-tail-length: 7.08em;
    --top-offset: 22.85vh;
    --fall-duration: 11.552s;
    --fall-delay: 4.978s;
  }
  .star:nth-child(5) {
    --star-tail-length: 5.13em;
    --top-offset: 76.18vh;
    --fall-duration: 11.491s;
    --fall-delay: 1.465s;
  }
  .star:nth-child(6) {
    --star-tail-length: 6.08em;
    --top-offset: 31.28vh;
    --fall-duration: 7.516s;
    --fall-delay: 9.249s;
  }
  .star:nth-child(7) {
    --star-tail-length: 5.14em;
    --top-offset: 11.34vh;
    --fall-duration: 6.055s;
    --fall-delay: 6.982s;
  }
  .star:nth-child(8) {
    --star-tail-length: 6.44em;
    --top-offset: 10.92vh;
    --fall-duration: 11.854s;
    --fall-delay: 7.17s;
  }
  .star:nth-child(9) {
    --star-tail-length: 6.29em;
    --top-offset: 56.37vh;
    --fall-duration: 8.574s;
    --fall-delay: 1.25s;
  }
  .star:nth-child(10) {
    --star-tail-length: 5.43em;
    --top-offset: 48.01vh;
    --fall-duration: 6.524s;
    --fall-delay: 7.259s;
  }
  .star:nth-child(11) {
    --star-tail-length: 6.2em;
    --top-offset: 36.36vh;
    --fall-duration: 6.403s;
    --fall-delay: 5.945s;
  }
  .star:nth-child(12) {
    --star-tail-length: 7.28em;
    --top-offset: 50.43vh;
    --fall-duration: 8.392s;
    --fall-delay: 1.598s;
  }
  .star:nth-child(13) {
    --star-tail-length: 7.18em;
    --top-offset: 69.83vh;
    --fall-duration: 9.764s;
    --fall-delay: 8.539s;
  }
  .star:nth-child(14) {
    --star-tail-length: 5.43em;
    --top-offset: 63.38vh;
    --fall-duration: 8.819s;
    --fall-delay: 7.592s;
  }
  .star:nth-child(15) {
    --star-tail-length: 6.57em;
    --top-offset: 6.09vh;
    --fall-duration: 7.966s;
    --fall-delay: 4.678s;
  }
  .star:nth-child(16) {
    --star-tail-length: 6.41em;
    --top-offset: 68.14vh;
    --fall-duration: 8.314s;
    --fall-delay: 8.052s;
  }
  .star:nth-child(17) {
    --star-tail-length: 6.35em;
    --top-offset: 72.69vh;
    --fall-duration: 9.259s;
    --fall-delay: 8.401s;
  }
  .star:nth-child(18) {
    --star-tail-length: 7.09em;
    --top-offset: 93.62vh;
    --fall-duration: 9.66s;
    --fall-delay: 5.856s;
  }
  .star:nth-child(19) {
    --star-tail-length: 6.2em;
    --top-offset: 83.23vh;
    --fall-duration: 6.602s;
    --fall-delay: 9.636s;
  }
  .star:nth-child(20) {
    --star-tail-length: 6.98em;
    --top-offset: 77.95vh;
    --fall-duration: 9.316s;
    --fall-delay: 0.282s;
  }
  .star:nth-child(21) {
    --star-tail-length: 5.19em;
    --top-offset: 7.67vh;
    --fall-duration: 10.172s;
    --fall-delay: 6.937s;
  }
  .star:nth-child(22) {
    --star-tail-length: 5.46em;
    --top-offset: 10.76vh;
    --fall-duration: 7.552s;
    --fall-delay: 9.685s;
  }
  .star:nth-child(23) {
    --star-tail-length: 5.69em;
    --top-offset: 47.65vh;
    --fall-duration: 6.183s;
    --fall-delay: 0.1s;
  }
  .star:nth-child(24) {
    --star-tail-length: 7.11em;
    --top-offset: 12.07vh;
    --fall-duration: 6.651s;
    --fall-delay: 1.602s;
  }
  .star:nth-child(25) {
    --star-tail-length: 5.43em;
    --top-offset: 32.41vh;
    --fall-duration: 6.741s;
    --fall-delay: 0.948s;
  }
  .star:nth-child(26) {
    --star-tail-length: 6.29em;
    --top-offset: 15.65vh;
    --fall-duration: 10.064s;
    --fall-delay: 5.51s;
  }
  .star:nth-child(27) {
    --star-tail-length: 7.11em;
    --top-offset: 72.41vh;
    --fall-duration: 7.54s;
    --fall-delay: 2.65s;
  }
  .star:nth-child(28) {
    --star-tail-length: 5.9em;
    --top-offset: 0.44vh;
    --fall-duration: 11.548s;
    --fall-delay: 6.974s;
  }
  .star:nth-child(29) {
    --star-tail-length: 6.78em;
    --top-offset: 6.04vh;
    --fall-duration: 11.426s;
    --fall-delay: 4.632s;
  }
  .star:nth-child(30) {
    --star-tail-length: 5.59em;
    --top-offset: 14.41vh;
    --fall-duration: 6.106s;
    --fall-delay: 2.757s;
  }
  .star:nth-child(31) {
    --star-tail-length: 6.86em;
    --top-offset: 99.43vh;
    --fall-duration: 11.127s;
    --fall-delay: 6.387s;
  }
  .star:nth-child(32) {
    --star-tail-length: 5.53em;
    --top-offset: 64.52vh;
    --fall-duration: 11.904s;
    --fall-delay: 9.696s;
  }
  .star:nth-child(33) {
    --star-tail-length: 7.3em;
    --top-offset: 69.65vh;
    --fall-duration: 6.002s;
    --fall-delay: 5.351s;
  }
  .star:nth-child(34) {
    --star-tail-length: 5.33em;
    --top-offset: 20.39vh;
    --fall-duration: 9.079s;
    --fall-delay: 3.014s;
  }
  .star:nth-child(35) {
    --star-tail-length: 5.02em;
    --top-offset: 76.32vh;
    --fall-duration: 8.372s;
    --fall-delay: 4.655s;
  }
  .star:nth-child(36) {
    --star-tail-length: 6.24em;
    --top-offset: 96.66vh;
    --fall-duration: 10.832s;
    --fall-delay: 1.519s;
  }
  .star:nth-child(37) {
    --star-tail-length: 5.77em;
    --top-offset: 71.05vh;
    --fall-duration: 7.565s;
    --fall-delay: 3.191s;
  }
  .star:nth-child(38) {
    --star-tail-length: 5.14em;
    --top-offset: 37.19vh;
    --fall-duration: 8.881s;
    --fall-delay: 8.507s;
  }
  .star:nth-child(39) {
    --star-tail-length: 6.43em;
    --top-offset: 65.42vh;
    --fall-duration: 8.281s;
    --fall-delay: 4.613s;
  }
  .star:nth-child(40) {
    --star-tail-length: 6.76em;
    --top-offset: 67.57vh;
    --fall-duration: 11.213s;
    --fall-delay: 6.753s;
  }
  .star:nth-child(41) {
    --star-tail-length: 6.89em;
    --top-offset: 54.49vh;
    --fall-duration: 11.399s;
    --fall-delay: 0.085s;
  }
  .star:nth-child(42) {
    --star-tail-length: 6.59em;
    --top-offset: 42.77vh;
    --fall-duration: 10.621s;
    --fall-delay: 1.953s;
  }
  .star:nth-child(43) {
    --star-tail-length: 5.89em;
    --top-offset: 14.57vh;
    --fall-duration: 11.082s;
    --fall-delay: 5.919s;
  }
  .star:nth-child(44) {
    --star-tail-length: 6.23em;
    --top-offset: 18.74vh;
    --fall-duration: 11.055s;
    --fall-delay: 2.949s;
  }
  .star:nth-child(45) {
    --star-tail-length: 6.16em;
    --top-offset: 52.85vh;
    --fall-duration: 7.317s;
    --fall-delay: 1.306s;
  }
  .star:nth-child(46) {
    --star-tail-length: 5.15em;
    --top-offset: 6.44vh;
    --fall-duration: 9.585s;
    --fall-delay: 3.725s;
  }
  .star:nth-child(47) {
    --star-tail-length: 7.27em;
    --top-offset: 73.33vh;
    --fall-duration: 7.472s;
    --fall-delay: 2.424s;
  }
  .star:nth-child(48) {
    --star-tail-length: 5.04em;
    --top-offset: 45.62vh;
    --fall-duration: 10.851s;
    --fall-delay: 3.59s;
  }
  .star:nth-child(49) {
    --star-tail-length: 7.47em;
    --top-offset: 62.99vh;
    --fall-duration: 8.465s;
    --fall-delay: 1.442s;
  }
  .star:nth-child(50) {
    --star-tail-length: 6.52em;
    --top-offset: 79vh;
    --fall-duration: 7.398s;
    --fall-delay: 8.222s;
  }
  .star::before, .star::after {
    position: absolute;
    content: '';
    top: 0;
    left: calc(var(--star-width) / -2);
    width: var(--star-width);
    height: 100%;
    background: linear-gradient(45deg, transparent, currentColor, transparent);
    border-radius: inherit;
    animation: blink 2s linear infinite;
  }
  .star::before {
    transform: rotate(45deg);
  }
  .star::after {
    transform: rotate(-45deg);
  }
  
  @keyframes fall {
    to {
      transform: translate3d(-30em, 0, 0);
    }
  }
  @keyframes tail-fade {
    0%, 50% {
      width: var(--star-tail-length);
      opacity: 1;
    }
    70%, 80% {
      width: 0;
      opacity: 0.6;
    }
    100% {
      width: 0;
      opacity: 0;
    }
  }
  @keyframes blink {
    50% {
      opacity: 0.6;
    }
  }


  
  
  #container {
    height: 400px;
    left: calc(50% - 200px);
    position: absolute;
    top: calc(50% - 200px);
    width: 400px;
  }
  #container #sun {
    background-color: yellow;
    border-radius: 50%;
    -webkit-box-shadow: 0 0 30px white;
            box-shadow: 0 0 30px white;
    height: 100px;
    left: 150px;
    position: absolute;
    top: 150px;
    width: 100px;
  }
  #container .orbit {
    border: solid;
    border-color: white transparent transparent transparent;
    border-radius: 50%;
    border-width: 1px 1px 0 0;
    -webkit-box-sizing: border-box;
            box-sizing: border-box;
    position: absolute;
    -webkit-transform: rotate(0deg);
            transform: rotate(0deg);
    -webkit-transform-origin: center;
            transform-origin: center;
  }
  #container .orbit#earth-orbit {
    -webkit-animation: orbit 36.5s linear infinite;
            animation: orbit 36.5s linear infinite;
    height: 300px;
    left: 50px;
    top: 50px;
    width: 300px;
  }
  #container .orbit#moon-orbit {
    -webkit-animation: orbit 2.7s linear infinite;
            animation: orbit 2.7s linear infinite;
    height: 80px;
    left: -25px;
    top: -25px;
    width: 80px;
  }
  #container .orbit .globe {
    border-radius: 50%;
    position: absolute;
  }
  #container .orbit .globe#earth {
    background: rgb(243, 121, 21);
    height: 30px;
    right: 28px;
    top: 28px;
    width: 30px;
  }
  #container .orbit .globe#moon {
    background: #ec9ae6;
    height: 12px;
    right: 2px;
    top: 8px;
    width: 12px;
  }
  
  @-webkit-keyframes orbit {
    to {
      -webkit-transform: rotate(360deg);
              transform: rotate(360deg);
    }
  }
  
  @keyframes orbit {
    to {
      -webkit-transform: rotate(360deg);
              transform: rotate(360deg);
    }
  }

  html,body,ul{
    margin: 0;
    padding: 0;
  }
  
  ul,li{
    list-style: none;
  }
  
  /*将每个li标签转化成行元素  因为我们到时候是将这些照片并排来排列显示  */
  ul li{
    display: inline;
  }
  /*再给ul设置一下宽度值和margin   margin四个值依次是上右下左 顺时针方向*/
  ul{
    width: 970px;
    margin:0 0 18px 10px ;
  }
  /*然后可以设置图片宽度，在没设置之前图片是占满了全屏*/
  ul img{
    display: block;/*转为块元素*/
    width: 190px;
    margin-bottom: 12px;
  }
  /*再接着给图片设置边框  注意我们这里是用a标签包裹了img图片  所以我们如果要对图片进行留白边操作的话就设置a标签*/
  ul a{
    background-color: #FFFFFF;
    display: inline;/*转为行元素*/
    float: left;/*左浮动*/
    width: auto;
    margin: 0 0 27px 30px;
    padding: 10px 10px 15px;/*上内边距是 10px; 右、左内边距是10px;下内边距是 15px*/
    text-decoration: none;
    font-size: 17px;
    color: #333333;
    /*这里设置的box-shadow四个值意思是：水平位移0;垂直位移3px;模糊半径6px;阴影颜色rgba(0,0,0,0.25)*/
    box-shadow: 0 3px 6px rgba(0,0,0,0.25) ;
    -webkit-box-shadow: 0 3px 6px rgba(0,0,0,0.25);
    -moz-box-shadow: 0 3px 6px rgba(0,0,0,0.25);
    -o-box-shadow: 0 3px 6px rgba(0,0,0,0.25);
    -ms-box-shadow: 0 3px 6px rgba(0,0,0,0.25);
  }
  
  ul li a:after{
    content: attr(title);
  }
  
  ul li:nth-child(even) a {
    -webkit-transform: rotate(2deg);
    -moz-transform: rotate(2deg);
    -ms-transform: rotate(2deg);
    transform: rotate(2deg);
  }
  ul li:nth-child(5n) a {
    -webkit-transform: rotate(5deg);
    -moz-transform: rotate(5deg);
    -ms-transform: rotate(5deg);
    transform: rotate(5deg);
    position: relative;
    right: 5px;
  }
  ul li:nth-child(8n) a {
    position: relative;
    top: 8px;
    right: 5px;
  }
  ul li:nth-child(11n) a {
    position: relative;
    top: 3px;
    right: -5px;
  }
  ul li a:hover{
    transform: scale(1.25);
    -webkit-transform: scale(1.25);
    -moz-transform: scale(1.25);
    -ms-transform: scale(1.25);
    -o-transform: scale(1.25);
    /*为了使放大效果更佳美观  所以我们也可以将鼠标悬停时的阴影（透明度这一块）加点改变*/
    box-shadow: 0 3px 6px rgba(0,0,0,0.25) ;
    -webkit-box-shadow: 0 3px 6px rgba(0,0,0,5);
    -moz-box-shadow: 0 3px 6px rgba(0,0,0,5);
    -o-box-shadow: 0 3px 6px rgba(0,0,0,5);
    -ms-box-shadow: 0 3px 6px rgba(0,0,0,5);
  }
  
  .menu3{
    width: 1000px;
    height: 40px;
    background-color: rgb(236, 159, 159);
}

.menu3 li{
    float: left;
    width: 120px;
    height: 40px;
    line-height: 40px;
    text-align: center;
}

.menu3 a{
    display: block;
    color: rgb(233, 35, 35);
    height: 40px;
    width: 120px;
    /* border-right: 1px solid #ccc; */
    border-bottom: 1px solid #a306a8;
    
}

.menu3 a:hover{
    background-color: rgb(91, 213, 235);
    color: rgb(247, 250, 51);
    border-bottom: 1px solid red;
}

.menu3 .submenu{
    visibility: hidden;
    width: 120px;
}

.menu3 li:hover .submenu{
    visibility: visible;
    position: relative;
    z-index: 100;
} 

.menu3 ,.submenu li{
    height: 40px;
    line-height: 40px;
}

.menu3 .submenu a{
    background-color: rgb(233, 138, 233);
    color: rgb(253, 232, 44);
    border: 0;
}

.menu3 .submenu a:hover{
    background-color: #333;
}


@media screen and (min-width: 1200px){
  h1{
      color: rgb(250, 28, 231);
  }
}

@media screen and (min-width: 980px) and (max-width: 1199px){
  h1{
      color: rgb(252, 97, 97);
  }
}

@media screen and (min-width: 768px) and (max-width: 979px){
  h1{
      color: rgb(252, 243, 168);
  }
}

@media screen and (min-width: 480px) and (max-width: 767px){
  h1{
      color: rgb(207, 255, 193);
  }
}

@media screen and (max-width: 479px){
  h1{
      color: rgb(241, 152, 253);
  }
}



/* 表格样式 */
.table_demo{
  font-size: 2rem;
  border: 1px solid black;
  width: 70%;
  margin: 0 auto;
  table-layout: fixed;
  caption-side: top;
  border-collapse: collapse;
    /* border-collapse: separate; */
  border-spacing: 10px;
  empty-cells: show;
}

.table_demo caption{
  font-size: 2.5rem;
}

.table_demo th, .table_demo td{
  border-top: 1px solid black;
  border-bottom: 1px solid black;
  text-align: center;
}

.table_demo thead{
  background-color: hsl(0, 94%, 37%);
  color: white;
}
.table_demo tbody tr:hover{
  background-color: yellow;
  cursor: pointer;
}

.table_demo tfoot td{
  text-align: right;
  padding-right: 2rem;
}

/* 表单样式 */
.form_demo{
  font-size: 1.4rem;
  border: 1px solids seagreen;
  background: url(图片/01.jpg);
  background-size:100% 100%; 
  width: 35rem;
  height: 25rem;
  text-align: left;

}

.form_demo input[type="text"], .form_demo input[type="password"] {
  border-left: 0;
  border-right: 0;
  border-top: 0;
  border-bottom: 1px solid #000;
  width: 200px;
  height: 21px;
  padding-left: 27px;
}
.form_demo #username{
  background: rgb(216, 207, 207) url(图片/username.png) no-repeat top left;
 
}

.form_demo #pwd{
  background: white url(图片/password.png) no-repeat top left;
 
}
.form_demo [type="submit"]{
  width: 100px;
  height: 38px;
  background-color: tomato;
  border: 1px dashed #2e5bec;
  border-radius: 10px;
  color: rgb(236, 244, 245);
  text-align: center;
}

.pos_fixed{
  background: url(图片/02.jpg);
  position: fixed;
  top: 0px;
  right: 50px;
  width: 300px;
  height: 150px;
  color: aliceblue;
  font-size: "宋体";
}


.search{
  width: 30%;          
  margin:80px auto;
  display: inline;
  top: 0px;
  left: 0px;

}
.search input{
  float: left;
  flex: 4;
  height: 30px;
  outline: none;
  border: 1px solid red;
  box-sizing: border-box;
  padding-left: 10px;
}
.search button{
  float: initial;
  flex: 1;
  height: 30px;
  background-color: red;
  color: white;
  border-style: none;
  outline: none;
}
.search button i{
  font-style: normal;
}
.search button:hover{
  font-size: 16px;
}

.footer {
	background: url(图片/00.jpg);
	width: 100%;
  clear:both;
	position:relative;
  bottom: 5px;
  color: rgb(18, 253, 69);
  font-size: "宋体";
  font-size: 9pt;
  line-height: 110%;
}


